Marrucciite is an extremely rare sulfosalt mineral primarily known from the Jas Roux locality in France. It typically occurs as small metallic, lead-gray grains associated with other sulfide and sulfosalt minerals in hydrothermal deposits.
Is this marrucciite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch marrucciite with a known reference. Marrucciite sits at Mohs 2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Marrucciite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Marrucciite typically shows a metallic luster.
- 4Match the color rangeCompare against the expected color range: lead-gray, black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: anhedral to subhedral grains.
Often confused with
Marrucciite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Marrucciite leaves black, Galena leaves lead-gray.
How to tell apart: Streak differs, so Marrucciite leaves black, Cinnabar leaves scarlet; luster reads metallic on Marrucciite and adamantine on Cinnabar.
How to tell apart: Streak differs, so Marrucciite leaves black, Stibnite leaves lead-gray.
Often found alongside marrucciite
Minerals reported to co-occur with marrucciite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Hg₃Pb₄Sb₆S₁₄
- Mohs hardness
- 2
- Density
- 6.35 g/cm³
- Streak
- Black
- Luster
- Metallic
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Anhedral to Subhedral Grains
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Veins in Sedimentary or Metamorphic Rocks
- Typical price
- $50-300 per specimen
Where rockhounds find marrucciite
Classic worldwide localities
- Jas Roux, Hautes-Alpes, France
Field-hunting tip
Look in hydrothermal veins in sedimentary or metamorphic rocks country, the host setting where marrucciite typically forms. If you start seeing cinnabar, stibnite, pyrite in float, you are in the right ground. Field specimens usually show a anhedral to subhedral grains habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find marrucciite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
